Field step size and temperature effects on the character of the magnetostructural transformation in a Gd5Ge4 single crystal
The critical magnetic fields required to induce the magnetostructural transformation below ∼30 K in Gd5Ge4 are dependent on the size of the magnetic-field step employed during isothermal measurements of magnetization: the smaller the step, the lower the critical field. The influence of the magnetic-field step size on the character of the magnetostructural transition in Gd5Ge4 diminishes as temperature increases, nearly disappearing above ∼30 K. Decreasing the size of the field step also leads to the formation of multiple steps in the magnetization. The steps are reproducible in the same sample at low temperatures (below ∼9 K) but they become stochastic and irreproducible at high temperatures (above ∼20 K). The varying dynamics of both the magnetization and demagnetization processes is associated with approaching true equilibrium states and, therefore, reduction of the size of the magnetic-field step at low temperatures plays a role similar to the dominant role of thermal fluctuations at high temperatures. Similar phenomena are expected to occur in other martensiticlike systems, e.g., the manganites.
This article is from Physical Review B 76, no. 13 (2007): 134406, doi:10.1103/PhysRevB.76.134406.